KR102058500B1 - Electrophotographic photosensitive member and electrophotographic apparatus mounted therewith - Google Patents

Abstract

The present invention provides an electrophotographic photosensitive member and an electrophotographic apparatus incorporating the same, which can reduce the amount of abrasion on the surface of the photosensitive member and can stably obtain a good image for a long time.
An electrophotographic photosensitive member comprising a conductive base 1 and a charge transport layer 4 provided on the conductive base. The charge transport layer contains an inorganic oxide filler surface-treated with a charge transport material, a resin binder, and a silane coupling agent, and the difference between the force terms (ΔSPa) between the dipoles of the Hansen solubility parameter between the charge transport material and the silane coupling agent is ΔSPa < The relationship of 1.0 is satisfied, and the difference (ΔSPb) of the London dispersion force term of the Hansen solubility parameter between the resin binder and the silane coupling agent satisfies the relationship of ΔSPb <2.5.

Description

Electrophotographic photosensitive member and electrophotographic apparatus mounted therewith

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrophotographic photosensitive member (hereinafter, also simply referred to as a "photosensitive member") used in an electrophotographic printer, a copying machine, a fax machine, and the like and an improvement of an electrophotographic apparatus equipped therewith.

The electrophotographic photosensitive member has a structure in which a photosensitive layer having a photoconductive function is provided on a conductive base. In recent years, research and development have been actively conducted on organic electrophotographic photosensitive members using organic compounds as functional components responsible for generating and transporting electric charges in accordance with advantages such as diversity of materials, high productivity, and safety. Application to the back is progressing.

[0003] In general, the photoconductor requires a function of maintaining surface charge in a dark place, a function of receiving light to generate charge, and a function of transporting generated charge. Examples of the photosensitive member include a so-called single layer photosensitive member having a single layer photosensitive layer having these functions, a charge generating layer mainly responsible for charge generation in light reception, and a surface charge in a dark place. There is a so-called laminated type (functional separation type) photosensitive member having a photosensitive layer in which a function is laminated as a charge transport layer that functions for transporting charges generated in the charge generating layer at the time of function and light reception.

The photosensitive layer is generally formed by applying a coating liquid obtained by dissolving or dispersing a charge generating material, a charge transporting material, and a resin binder in an organic solvent on a conductive substrate. Particularly, for the layer that forms the outermost surface of the organic photoconductor, it is resistant to friction generated between the paper and the blade for removing the toner, and has excellent flexibility and good transparency of exposure. There are many cases where carbonate is used as the resin binder. Especially, bisphenol Z-type polycarbonate is widely used as a resin binder. As a resin binder, the technique using this polycarbonate is described in patent document 1 etc.

On the other hand, as a recent electrophotographic apparatus, monochromatic light such as argon, helium-neon, semiconductor laser, or light emitting diode is used as an exposure light source, and information such as images and characters are digitalized to be converted into optical signals. The so-called digital apparatus which forms an electrostatic latent image on the surface of a photosensitive member by making it irradiate and irradiate light on the charged photosensitive member, and visualizes it with a toner is mainstream.

As a method of charging the photosensitive member, the charging member and the photosensitive member consisting of a non-contact charging method in which the charging member and the photosensitive member such as scorotron and the photosensitive member are non-contact, and a semi-conductive rubber roller or brush There is a contact charging system in which is in contact with. Among these, the contact charging method has a feature that corona discharge occurs very close to the photoconductor as compared with the non-contact charging method, so that ozone is generated less and the applied voltage is low. Therefore, since the electrophotographic apparatus which is more compact, low cost, and low environmental pollution can be implement | achieved, it is mainstream especially in the medium-sized apparatus.

As means for cleaning the surface of the photoconductor, a scraping by a blade, a simultaneous cleaning process by a blade, and the like are mainly used. In the cleaning process by the blades, untransferred residual toner on the surface of the photoconductor may be scraped off by the blades and collected in a recovery box for waste toner, or returned to a developing machine. Therefore, when using a scraping type cleaner by such a blade, a space for a recovery box or recycling of toner is required, and it is necessary to monitor whether the recovery box is full. In addition, when paper powder or external additives remain on the blade, scratches may occur on the surface of the photoconductor, thereby shortening the life of the photoconductor. Therefore, there may be a case where a toner is recovered in the developing process or a process of magnetically or electrically sucking the remaining toner adhered to the photosensitive member surface immediately before the developing process.

In addition, when using a cleaning blade, it is necessary to increase the hardness and contact pressure of the blade in order to improve the cleaning properties. For this reason, the abrasion of the surface of a photosensitive member is accelerated | stimulated, a dislocation fluctuation and a sensitivity fluctuation arise, an image abnormality arises, and a color apparatus may have a problem with color balance and reproducibility.

In order to solve this problem, various improvement methods of the outermost surface layer of the photoconductor have been proposed. For example, in patent documents 2 and 3, the method of adding a filler to the surface layer of a photosensitive member is proposed in order to improve the durability of the photosensitive member surface. However, it is difficult to uniformly disperse the filler by the method of dispersing the filler in the layer. In addition, as the aggregate of the filler is present, the transmittance of the layer is lowered, or the filler scatters the exposure light, charge transport and charge generation become uneven, and there is a possibility that the image characteristics may be lowered. Furthermore, there is also a method of adding a dispersant in order to improve the dispersibility of the filler. In this case, since the dispersant itself affects the photosensitive member characteristics, it was difficult to achieve both the dispersibility and the photosensitive member characteristics of the filler.

In order to solve such a damage, for example, in patent documents 4 and 5, the technique of improving content of a filler and a dispersion state is proposed. However, the effect by these techniques is not enough, and development of the electrophotographic photosensitive member which can achieve chain resistance, repeat stability, and high resolution is desired.

[0011] Further, Patent Document 6 discloses a number average primary particle size (Dp) of 5 to 100 nm which is subjected to a plurality of surface treatments and subjected to surface treatment with silazane compounds as the last surface treatment. An organic photoconductor containing inorganic particles in a surface layer is disclosed, and Patent Document 7 discloses an electrophotographic photoconductor containing a predetermined amount of silica particles in a photosensitive layer on the outermost surface with a predetermined functional material. .

Japanese Patent Publication No. S61-62040 Japanese Patent Laid-Open No. H01-205171 Japanese Patent Laid-Open No. H07-333881 Japanese Patent Publication H08-305051 Japanese Patent Publication No. 2006-201744 Japanese Patent Publication No. 2006-301247 Japanese Patent Publication No. 2015-175948 Japanese Patent Laid-Open No. 2004-143028 Japanese Patent Publication No. 2013-224225

As described above, the improvement of the surface layer of the photoconductor has been studied in various ways, but in the technique disclosed in the patent document, the examination of the relationship between the components of the surface layer has not been sufficiently made, and the surface of the photoconductor is It was not possible to stably and sufficiently secure the electrical characteristics and the image characteristics while sufficiently reducing the amount of wear.

Accordingly, an object of the present invention is to solve the above problems, to reduce the amount of wear on the surface of the photoconductor, and to provide an electrophotographic photosensitive member and an electrophotographic apparatus equipped therewith capable of obtaining a good image stably over a long period of time. Is in.

MEANS TO SOLVE THE PROBLEM The present inventors mix | blended the combination of the charge transport material, resin binder, and silane coupling surface treatment filler with favorable compatibility to the layer used as a photosensitive body result as a result of careful examination in order to solve the said subject. By this, fillers were uniformly dispersed in the layer, and it was found that a highly durable electrophotographic photosensitive member could be realized, and thus the present invention was completed.

That is, in the first aspect of the present invention, a conductive base and

An electrophotographic photosensitive member comprising a charge transport layer provided on the conductive base,

The charge transport layer contains an inorganic oxide filler surface-treated with a charge transport material, a resin binder, and a silane coupling agent,

The difference (ΔSPa) of the force term between dipoles of Hansen solubility parameters between the charge transport material and the silane coupling agent satisfies the relationship of ΔSPa <1.0. Also,

The difference ΔSPb of the London dispersion force term of the Hansen solubility parameter between the resin binder and the silane coupling agent satisfies the relationship of ΔSPb <2.5.

Here, the Hansen solubility parameter is calculated using Hansen's equation that can divide the interaction between the intermolecular forces into the London dispersion force term, dipole force term, and hydrogen bonding force term. . Among them, the force term δp between the dipoles of the Hansen solubility parameter is calculated by the following equation.

^{δp = √ΣFp 2 / V (J} 1/2 / ㎝ 3/2)

Where Fp is the cohesive energy of the Kreveren and Hoftyzer parameters related to the dipoles of each component, and V is the molar volume of each component.

In addition, the London dispersion force term (δd) of the Hansen solubility parameter is calculated by the following equation.

^{δd = ΣFd / V (J 1/2} / ㎝ 3/2)

Where Fd is the cohesive energy of the Kreveren and Hoftyzer parameters related to the London dispersion of each component, and V is the molar volume of each component.

In addition, in this invention, in order to take the difference between two types of materials with respect to each term of the said solubility parameter, the force term between the dipoles of a Hansen solubility parameter is represented by SPa and the London dispersion force term by SPb.

In addition, with respect to the above formula, the values corresponding to the cohesive energy density and the molar volume values for the individual components are databased for each atomic group (Kreveren and Hoftyzer parameter), and are introduced in the literature. .

[0019] The present inventors have examined the correlation between each term of the Hansen solubility parameter, the compatibility between the charge transport material and the silane coupling agent, and the correlation between the compatibility between the resin binder and the silane coupling agent, respectively. We found that the former had a high correlation to the difference in the force terms between the dipoles and the latter to the difference in the London dispersion force terms. Here, the charge transport material and the resin binder have been confirmed to have good compatibility in the range of materials commonly used in the photoconductor field. In the present invention, between the charge transport material and the silane coupling agent, and the resin The compatibility between a binder and a silane coupling agent is examined. According to the investigation by the present inventors, the difference (ΔSPa) of the force term between the dipoles of the Hansen solubility parameter between the charge transport material and the silane coupling agent satisfies the relationship of ΔSPa <1.0, and the Hansen between the resin binder and the silane coupling agent By using a composition whose difference (ΔSPb) in the London dispersion force term of the solubility parameter satisfies the relationship of ΔSPb <2.5 for the charge transport layer of the photoconductor, good chain resistance can be obtained. This is considered to be because the filler contained in the charge transport layer is uniformly dispersed, the strength of the layer is improved, and the wear resistance is improved by setting the material composition of the charge transport layer in which the values of ΔSPa and ΔSPb fall within the above ranges.

The resin binder is preferably a polycarbonate resin or a polyarylate resin. Moreover, it is preferable that the said inorganic oxide filler has a primary particle diameter of 1-200 nm. Furthermore, the charge transport material is suitably a hole transport material. The photoconductor may include at least an undercoat layer, a charge generation layer, and the charge transport layer on the conductive substrate in this order.

In addition, in the second aspect of the present invention, the electrophotographic apparatus may mount the electrophotographic photosensitive member.

According to the above aspect of the present invention, by using the photosensitive layer having the specific charge transport layer composition, it is possible to reduce the amount of wear on the surface of the photoconductor while maintaining the electrophotographic characteristics of the photoconductor, and to obtain a good image stably over a long period of time. At the same time, it has become clear that mechanical strength can be improved. This is because the filler contained in the layer is uniformly dispersed by blending a combination of a charge transport material, a resin binder, and a silane coupling surface treatment filler having a uniform compatibility in the charge transport layer, whereby the external force applied to the photosensitive layer ( It is thought that the durability to abrasion due to external force is improved, the light transmittance of the layer is improved, scattering of exposure light is prevented, and as a result, a high quality photosensitive member having high abrasion resistance and excellent image quality characteristics can be provided.

1 is a schematic cross-sectional view showing an example of the negatively charged function-separated stacked electrophotographic photosensitive member of the present invention.
2 is a schematic configuration diagram showing an example of the electrophotographic apparatus of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, specific embodiment of the electrophotographic photosensitive member of this invention is described in detail using drawing. This invention is not limited at all by the following description.

1 is a schematic cross-sectional view showing an example of the electrophotographic photosensitive member of the present invention, and shows a negatively charged type electrophotographic photosensitive member. As shown, in the negatively charged laminated photosensitive member, the undercoat layer 2, the charge generating layer 3 having the charge generating function, and the charge transporting layer 4 having the charge transport function are formed on the conductive substrate 1. ) Are stacked one by one. In addition, you may provide the undercoat layer 2 as needed.

The conductive base 1 may be a support of each layer constituting the photoconductor at the same time as the electrode of the photoconductor, and may be any shape such as a cylindrical shape, a plate shape, or a film shape. As a material of the electroconductive base 1, metals, such as aluminum, stainless steel, and nickel, or the thing which gave electroconductive treatment to the surface of glass, resin, etc. can be used.

The undercoat layer 2 consists of a metal oxide film, such as a layer containing resin as a main component, and almite. The undercoat 2 is used for controlling the injectability of the charge from the conductive base 1 to the photosensitive layer, for coating the surface defects of the conductive base 1, for improving the adhesion between the photosensitive layer and the conductive base 1, and the like. For the purpose, it is installed as needed. Examples of the resin material used for the undercoat layer 2 include insulating polymers such as casein, polyvinyl alcohol, polyamide, melamine, and cellulose, and conductive polymers such as polythiophene, polypyrrole, and polyaniline. In addition, it can mix and use suitably. In addition, these resins may be used by containing metal oxides such as titanium dioxide and zinc oxide.

The charge generating layer 3 is formed by a method such as applying a coating liquid in which particles of a charge generating material are dispersed in a resin binder, and receives charges to generate charges. The charge generating layer 3 has a high charge generating efficiency and an injection property of the generated charges into the charge transport layer 4 is important, and it is preferable that the charge generating layer 3 has a low electric field dependence and good injection even at a low electric field. .

As the charge generating material, X-type metal-free phthalocyanine, τ-type metal-free phthalocyanine, α-type titanyl phthalocyanine, β-type titanyl phthalocyanine, Y-type titanyl phthalocyanine, γ-type titanyl phthalocyanine, amorphous (amorphous) type Phthalocyanine compounds such as tanylphthalocyanine and ε-type copper phthalocyanine, various azo pigments, anthrone pigments, thiapyryllium pigments, perylene pigments, perinone pigments, squarylium pigments, quinacridone pigments, and the like, alone or as appropriate combinations It can be used, and a suitable material can be selected according to the light wavelength region of the exposure light source used for image formation.

As the resin binder of the charge generation layer 3, polycarbonate resin, polyester resin, polyamide resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, phenoxy resin, polyvinyl acetal resin, polyvinyl buty A polymer, a copolymer of a ral resin, a polystyrene resin, a polysulfone resin, a diallyl phthalate resin, a methacrylic acid ester resin, or the like can be used in appropriate combination.

In addition, the content of the charge generating material in the charge generating layer 3 is preferably 20 to 80% by mass, more preferably 30 to 70% by mass with respect to the solid content in the charge generating layer (3). to be. Moreover, content of the resin binder in the charge generation layer 3 is 20-80 mass% suitably with respect to solid content in the charge generation layer 3, More preferably, it is 30-70 mass%.

Since the charge generating layer 3 may have a charge generating function, the film thickness thereof is generally 1 μm or less, and preferably 0.5 μm or less. The charge generating layer 3 can be used by mainly using a charge generating material and adding a charge transport material or the like thereto.

The charge transport layer 4 is mainly composed of a charge transport material, a resin binder, and an inorganic oxide filler surface-treated with a silane coupling agent. In the embodiment of the present invention, as the charge transport material, the resin binder, and the silane coupling agent surface treatment filler of the charge transport layer 4, the difference in force terms (ΔSPa) between the dipoles of the Hansen solubility parameter between the charge transport material and the silane coupling agent ) Satisfies the relationship of ΔSPa <1.0, and further uses a composition in which the difference (ΔSPb) in the London dispersion force term of the Hansen solubility parameter between the resin binder and the silane coupling agent satisfies the relationship of ΔSPb <2.5. As a result, the compatibility between the charge transport material and the resin binder and the silane coupling agent in the charge transport layer 4 constituting the surface of the photoconductor can be improved, and the dispersibility of the inorganic oxide filler can be enhanced, thereby sufficiently reducing the amount of wear on the surface of the photoconductor. In doing so, the electrical characteristics and the image characteristics can be secured satisfactorily. Said (DELTA) SPa is suitably (DELTA) SPa <= 0.95, and it is so preferable that it is small. Moreover, said (DELTA) SPb is suitably (DELTA) SPb <= 2.35, and it is so preferable that it is small.

In the embodiment of the present invention, the charge transport material used for the charge transport layer 4 is suitably a hole transport material. As a charge transport material, a resin binder, and a silane coupling agent which can be used in embodiment of this invention, the following charge transport materials (A1-A9), resin binders (B1-B4), and a silane coupler are respectively respectively mentioned. Although ring agent (C1-C5) is mentioned, it is not limited to these. Especially, as a resin binder, polycarbonate resins, such as bisphenol Z-type and bisphenol Z-biphenyl copolymer, and polyarylate resin which are illustrated below can be used suitably.

[0035]

[0036]

[0037]

In Tables 1 and 2 below, the charge transport material (A1 ~ A9), the resin binder (B1 ~ B4) and the silane coupling agent (C1 ~ C5) satisfying the relationship between the difference (ΔSPa and ΔSPb) of the solubility parameter The specific example of the combination of the following is shown.

[0039] [Table 1]

[0040] [Table 2]

In addition, the weight average molecular weight of the resin binder is preferably 5000 to 250000 in the GPC (gel permeation chromatography) analysis by polystyrene conversion, more preferably 10000 to 200000.

In the embodiment of the present invention, the charge transport layer 4 contains an inorganic oxide filler surface-treated with a silane coupling agent. Examples of the inorganic oxide filler include silica as a main component, alumina, zirconia, titanium oxide, tin oxide, zinc oxide, and the like, and these usually have a hydroxyl group on the surface when in use. For this reason, when the inorganic oxide filler is mixed in the coating liquid as it is, the inorganic oxide fillers are easily aggregated. However, by treating the inorganic oxide with a silane coupling agent, the silane coupling agent is bonded to the hydroxyl group on the surface of the inorganic oxide, and the cohesiveness of the inorganic oxide itself is achieved. In addition, the compatibility with the resin binder and the charge transport material in the coating liquid can be improved. However, even in the case of the inorganic oxide filler surface-treated with a silane coupling agent, hydroxyl groups may remain on the surface depending on the degree of surface treatment, which causes aggregation.

Among the above, as the inorganic oxide, an inorganic oxide containing silica as a main component is preferable. As a method for producing silica particles having a particle diameter of several nm to several tens of nm as silica, a method of producing water glass called a wet method as a raw material or a dry method The method of making chlorosilane etc. react in a gas phase, the method of using the alkoxide as a silica precursor as a raw material, etc. are known.

[0044] Here, if a large amount of dissimilar metals are present as impurities when surface-treating silica, defects are caused by metals different from ordinary oxide sites, and the charge distribution on the surface fluctuates. This improves the cohesiveness of the oxide particles, and consequently leads to an increase in the aggregates in the coating liquid and the photosensitive layer. Therefore, the purity of the silica is preferably high purity. Therefore, it is preferable to control content of metals other than the metal element which comprises an inorganic oxide to 1000 ppm or less with respect to each metal element.

On the other hand, in order to sufficiently react the surface treatment agent to improve the activity of the silica surface, it is suitable to add a trace amount of the other kind of metal. The surface treating agent reacts with the hydroxyl group present on the surface of the silica, but when the silica contains a small amount of other metal element, the other metal element present on the surface of the silica is affected by the difference in electronegativity between the metals. The reactivity of the silanol group (hydroxyl group) adjacent to is improved. Since the hydroxyl group has high reactivity with the surface treating agent, the hydroxyl group reacts with the surface treating agent more firmly than other hydroxyl groups and, if remaining, causes aggregation. After the reaction of such a surface treating agent, the surface treating agent reacts with another hydroxyl group, and it is thought that the cohesiveness of silica is greatly improved by the effect of the surface treating agent and the effect of reducing the deflection of the surface charge by the dissimilar metal on the surface. In embodiment of this invention, when an inorganic oxide contains a trace amount of another metal, since the reactivity of a surface treating agent becomes more favorable and the dispersibility by surface treatment improves as a result, it is preferable. The improvement of the cohesiveness when the said dissimilar metal exists in a large quantity as an impurity, and the improvement of the dispersibility by containing such a trace amount of a different kind of metal can be said to be due to another mechanism.

Regarding the silica, when the aluminum element is added in a range up to 1000 ppm or less, it is suitable for surface treatment. The adjustment of the amount of aluminum element in the silica can be carried out using the methods described in Japanese Patent Laid-Open No. 2004-143028, Japanese Patent Laid-Open No. 2013-224225, and the like, as long as it can be controlled to a desired range. There is no restriction | limiting in particular about the adjustment method. Specifically, as a method of more suitably controlling the amount of aluminum elements on a silica surface, there exist the following methods, for example. First, when producing silica fine particles, a method of controlling the amount of aluminum on the silica surface by growing silica particles in a shape smaller than the desired silica particle diameter and then adding aluminum alkoxide serving as an aluminum source, have. In addition, there are a method of placing silica fine particles in a solution containing aluminum chloride, coating an aluminum chloride solution on the surface of silica fine particles, drying and firing them, or reacting a mixed gas of an aluminum halide compound and a silicon halide compound. .

In addition, the structure of the silica, a plurality of silicon atoms and oxygen atoms are known to take the form of a mesh-like bond structure in a ring-shaped (環狀 目), in the case of containing an aluminum element, the cyclic structure of silica The number of atoms constituting the compound is larger than ordinary silica due to the effect of mixing aluminum. By this effect, steric hindrance when the surface treatment agent reacts with respect to the hydroxyl group on the surface of the silica containing aluminum element is alleviated than that of the normal silica surface, and the reactivity of the surface treatment agent is improved. It becomes a surface-treated silica with improved dispersibility than when the surface treatment agent is reacted.

Moreover, in order to provide the effect of embodiment of this invention, in controlling the amount of aluminum elements, the silica by a wet method is more suitable. Moreover, 1 ppm or more is suitable for content of the aluminum element with respect to silica, considering the reactivity of a surface treating agent.

Although it does not specifically limit as a form of an inorganic oxide, In order to reduce cohesion and obtain a uniform dispersion state, it is preferable that the sphericity of an inorganic oxide is 0.8 or more, and it is more preferable that it is 0.9 or more.

In addition, when using an inorganic oxide in the charge transport layer of the photoconductor with which high resolution is anticipated, it is preferable to consider the influence by alpha rays etc. derived from the material added to a charge transport layer. For example, using a semiconductor memory device as an example, the memory device maintains the type of data to be stored depending on whether or not there is charge accumulation. However, as the size of the micrometer decreases, the amount of charge accumulated also becomes smaller, and is changed by? Rays irradiated from the outside. The kind of data is changed by the electric charge to a degree, and as a result, an unexpected change of data occurs. In addition, since the magnitude of the current flowing through the semiconductor element is also small, the current (noise) generated by the? Line becomes relatively large even when compared with the magnitude of the signal, which may cause malfunction. Similarly to this phenomenon, in consideration of the influence on the movement of the charges in the charge transport layer of the photoconductor, it is more suitable to use a material having less α rays as the film constituent material. Specifically, it is effective to reduce the concentrations of uranium and thorium in the inorganic oxide, preferably thorium is 30 ppb or less, and uranium is 1 ppb or less. As a manufacturing method which reduces the amount of uranium and thorium in an inorganic oxide, although it is described in Unexamined-Japanese-Patent No. 2013-224225 etc., if it is possible to reduce the density | concentration of these elements, it is not limited to this method.

Although the primary particle diameter (primary particle size) of the inorganic oxide filler is not particularly limited, it is preferably 1 to 200 nm, more preferably 5 to 100 nm, even more preferably 10-50 nm. If the primary particle diameter of an inorganic oxide filler is less than 1 nm, a dispersion state may become nonuniform by aggregation. On the other hand, when the primary particle diameter of an inorganic oxide filler exceeds 200 nm, scattering of light may become large and an image loss may occur. In addition, a primary particle diameter is the number average diameter measured using the scanning microscope which can observe the surface shape of particle | grains directly.

As content of the surface-treated inorganic oxide filler in the charge transport layer 4, it is 1-40 mass% with respect to solid content of the charge transport layer 4, More preferably, it is 2-30 mass%. As content of the resin binder in the charge transport layer 4, it is 20-90 mass% suitably with respect to solid content of the charge transport layer 4 except an inorganic oxide filler, More preferably, it is 30-80 mass%. As content of the charge transport material in the charge transport layer 4, it is 10-80 mass% suitably with respect to solid content of the charge transport layer 4 except an inorganic oxide filler, More preferably, it is 20-70 mass%.

Furthermore, as the film thickness of the charge transport layer 4, in order to maintain a practically effective surface potential, the range of 3-50 micrometers is preferable, and the range of 15-40 micrometers is more preferable.

In the embodiment of the present invention, the charge generating layer 3 and the charge transport layer 4, as desired, for the purpose of improving the resistance to the environment and stability to harmful light, antioxidant and light Deterioration inhibitors, such as a stabilizer, can be contained. Examples of the compound used for this purpose include chromanol derivatives such as tocopherol and esterified compounds, polyarylalkane compounds, hydroquinone derivatives, etherified compounds, dietherized compounds, benzophenone derivatives, benzotriazole derivatives, and thio Ether compounds, phenylene diamine derivatives, phosphonic acid esters, phosphorous acid esters, phenolic compounds, hindered phenolic compounds, straight chain amine compounds, cyclic amine compounds, hindered amine compounds and the like. have.

In addition, in the charge generating layer 3 and the charge transport layer 4, a leveling agent such as silicone oil or fluorine oil may be contained for the purpose of improving the leveling property of the formed film or imparting lubricity. It may be. Further, metals such as silicon oxide (silica), titanium oxide, zinc oxide, calcium oxide, aluminum oxide (alumina), zirconium oxide, etc., for the purpose of adjusting the film hardness, reducing the friction coefficient, imparting lubricity, and the like. Metal sulfates such as oxides, barium sulfate and calcium sulfate, fine particles of metal nitrides such as silicon nitride and aluminum nitride, or fluorine resin particles such as tetrafluoroethylene resin, fluorine comb-grafted graft polymer resin and the like. Furthermore, if necessary, other well-known additives can also be contained in the range which does not spoil an electrophotographic characteristic remarkably.

[0056] The electrophotographic photosensitive member of the embodiment of the present invention can obtain a desired effect by applying to various machine processes. Specifically, a charging process such as a contact charging method using a charging member such as a roller or a brush, a non-contact charging method using a corotron, a scorotron and the like, and a phenomenon such as a nonmagnetic one component, a magnetic one component, and a two component Sufficient effects can also be obtained in development processes such as contact development and non-contact development using a system (developer).

[0057] (electrophotographic device)

The electrophotographic apparatus of the embodiment of the present invention is characterized by mounting the electrophotographic photosensitive member of the embodiment of the present invention. 2, the schematic block diagram of one structural example of the electrophotographic apparatus which concerns on this invention is shown. The electrophotographic apparatus 60 of embodiment of this invention shown shows the electroconductive base 1 and the undercoat layer 2 and the photosensitive layer 300 which were coat | covered on the outer peripheral surface of the embodiment of this invention. The photosensitive member 7 is mounted. The electrophotographic apparatus 60 supplies a roller-type charging member 21 and an applied voltage to the charging member 21 in the illustrated example, which is disposed at the outer peripheral edge portion of the photosensitive member 7. A feeding member including a high pressure power supply 22, an image exposure member 23, a developing unit 24 having a developing roller 241, a feeding roller 251, and a feeding guide 252 ( 25) and a transfer charger (direct charging type) 26. The electrophotographic apparatus 60 may further include the cleaning apparatus 27 provided with the cleaning blade 271, and the antistatic member 28. Moreover, the electrophotographic apparatus 60 of embodiment of this invention can be a color printer.

(Example)

Hereinafter, specific embodiments of the present invention will be described in more detail with reference to Examples. The present invention is not limited by the following examples as long as the gist of the present invention is not exceeded.

(Manufacture of negatively charged laminated photosensitive member)

(Example 1)

5 mass parts of alcohol-soluble nylon (Toray Corporation, brand name "CM8000") and 5 mass parts of titanium oxide fine particle processed by aminosilane were melt | dissolved and disperse | distributed to 90 mass parts of methanol, and the coating liquid 1 was prepared. The coating liquid 1 is immersed in an outer periphery of an aluminum cylinder having an outer diameter of 30 mm as the conductive base 1, dried at a temperature of 100 ° C. for 30 minutes, and an undercoat layer having a thickness of 3 μm. (2) was formed.

Next, 1 part by mass of Y-type titanyl phthalocyanine as a charge generating material, and polyvinyl butyral resin as a resin binder (manufactured by Sekisui Kagaku Co., Ltd., trade name "Esrek (S-LEC) BM-2) 1.5 mass parts was melt | dissolved and disperse | distributed to 60 mass parts of dichloromethane, and the coating liquid 2 was prepared. The coating liquid 2 was immersed and coated on the undercoat layer 2, and dried at a temperature of 80 ° C. for 30 minutes to form a charge generating layer 3 having a thickness of 0.3 μm.

Next, the following structural formula (I-1) as a charge transport material,

9 parts by mass of the compound (A1) represented by the following, and the following structural formula (II-1) as a resin binder,

11 mass parts of resin (B1) which has a repeating unit represented by this was melt | dissolved in 80 mass parts of tetrahydrofuran. In this liquid, as an inorganic oxide filler surface-treated with a silane coupling agent, silica (YA010C, aluminum element content 500 ppm) manufactured by Admatechs Company Limited, was represented by the following structural formula (III-1),

5 weight part of surface-treated silica which surface-treated with the silane coupling agent (C2) shown by this was mixed and dispersed, and the coating liquid 3 was produced. The coating liquid 3 was immersed-coated on the said charge generation layer 3, and it dried for 60 minutes at the temperature of 120 degreeC, the charge transport layer 4 of 20 micrometers in thickness was formed, and the negatively charged laminated photosensitive member was produced.

[0062] (Example 2)

Resin binder (B1) represented by Structural Formula (II-1) used in Example 1 was represented by Structural Formula (II-2),

Except having changed into the resin binder (B2) shown by the following, the photosensitive member was produced by the method similar to Example 1.

(Example 3)

Resin binder (B1) represented by Structural Formula (II-1) used in Example 1 was represented by Structural Formula (II-3),

Except having changed into the resin binder (B3) shown by the following, the photosensitive member was produced by the method similar to Example 1.

(Example 4)

The charge transport material (A1) represented by Structural Formula (I-1) used in Example 1 was represented by Structural Formula (I-2),

A photosensitive member was produced in the same manner as in Example 1 except for changing to the charge transport material (A2) shown in FIG.

(Example 5)

The charge transport material (A1) represented by Structural Formula (I-1) used in Example 1 was represented by Structural Formula (I-3),

Except having changed into the charge transport material (A3) shown by the following, the photosensitive member was produced by the method similar to Example 1.

(Example 6)

The charge transport material (A1) represented by Structural Formula (I-1) used in Example 1 was represented by Structural Formula (I-4),

Except having changed into the charge transport material (A7) shown by the following, the photosensitive member was produced by the method similar to Example 1.

(Example 7)

The charge transport material (A1) represented by Structural Formula (I-1) used in Example 1 was represented by Structural Formula (I-5),

Except having changed into the charge transport material (A8) shown by the following, the photosensitive member was produced by the method similar to Example 1.

(Example 8)

The charge transport material (A1) represented by Structural Formula (I-1) used in Example 1 was represented by Structural Formula (I-6),

Except having changed into the charge transport material (A9) shown by the following, the photosensitive member was produced by the method similar to Example 1.

(Example 9)

The silane coupling agent (C2) represented by Structural Formula (III-1) used in Example 1 is represented by Structural Formula (III-2),

Except having changed into the silane coupling agent (C3) shown by the following, the photosensitive member was produced by the method similar to Example 1.

(Example 10)

The charge transport material (A1) represented by Structural Formula (I-1) used in Example 1 was represented by Structural Formula (I-2),

The resin binder (B1) represented by Structural Formula (II-1) was replaced with the charge transport material (A2) represented by the following Structural Formula (II-2),

The silane coupling agent (C2) represented by Structural Formula (III-1) was replaced with the resin binder (B2) represented by the following Structural Formula (III-3),

Except having changed into the silane coupling agent (C4) shown by the following, the photosensitive member was produced by the method similar to Example 1.

[0071] (Example 11)

Resin binder (B1) represented by Structural Formula (II-1) used in Example 1 was represented by Structural Formula (II-2),

The silane coupling agent (C2) represented by Structural Formula (III-1) was replaced with the resin binder (B2) represented by the following Structural Formula (III-4),

Except having changed into the silane coupling agent (C5) shown by the following, the photosensitive member was produced by the method similar to Example 1.

(Example 12)

Resin binder (B1) represented by Structural Formula (II-1) used in Example 1 was represented by Structural Formula (II-4),

The silane coupling agent (C2) represented by Structural Formula (III-1) was replaced with the resin binder (B4) represented by the following Structural Formula (III-4),

Except having changed into the silane coupling agent (C5) shown by the following, the photosensitive member was produced by the method similar to Example 1.

[0073] (Comparative Example 1)

The silane coupling agent (C2) represented by Structural Formula (III-1) used in Example 1 is represented by Structural Formula (III-5),

Except having changed into the silane coupling agent shown by the following, the photosensitive member was produced by the method similar to Example 1.

[0074] (Comparative Example 2)

The silane coupling agent (C2) represented by Structural Formula (III-1) used in Example 1 is represented by Structural Formula (III-6),

Except having changed into the silane coupling agent shown by the following, the photosensitive member was produced by the method similar to Example 1.

[0075] (Comparative Example 3)

The silane coupling agent (C2) represented by Structural Formula (III-1) used in Example 1 is represented by Structural Formula (III-7),

Except having changed into the silane coupling agent shown by the following, the photosensitive member was produced by the method similar to Example 1.

[0076] (Comparative Example 4)

The silane coupling agent (C2) represented by Structural Formula (III-1) used in Example 1 is represented by Structural Formula (III-8),

A photosensitive member was produced in the same manner as in Example 1 except for changing to a charge transport material represented by.

[0077] (Comparative Example 5)

The silane coupling agent (C2) represented by Structural Formula (III-1) used in Example 3 is represented by Structural Formula (III-2),

Except having changed into the silane coupling agent (C3) shown by the following, the photosensitive member was produced by the method similar to Example 3.

[0078] (Comparative Example 6)

The photosensitive member was produced by the method similar to Example 1 except not adding the surface-treated silica which surface-treated with the silane coupling agent used in Example 1.

For the photoconductors produced in Examples 1 to 12 and Comparative Examples 1 to 6 described above, the difference between the force terms between the dipoles of the Hansen solubility parameter (ΔSPa) between the charge transport material and the silane coupling agent, and the resin binder The value of the difference (ΔSPb) of the London dispersion force term of the Hansen solubility parameter between silane coupling agents was determined. The results are shown in Table 3 below with the composition of each photoconductor.

<Evaluation of Photosensitive Body>

The electrical characteristics of the photosensitive bodies produced in Examples 1-12 and Comparative Examples 1-6 mentioned above were evaluated by the following method. The evaluation results are shown in Table 4 below.

<Electrical Characteristics>

The electrical characteristics of the photoconductor obtained by each Example and the comparative example were evaluated by the following method using the process simulator (CYNTHIA91) manufactured by Zentech. The surface potentials immediately after the charging of the photoconductors of Examples 1 to 12 and Comparative Examples 1 to 6 after charging the surface of the photoconductor at -650 V in a dark place by corona discharge in a dark environment. (V0) was measured. Subsequently, after leaving for 5 seconds in a dark place, the surface potential (V5) was measured, and the following formula (1),

Vk5 = V5 / V0 × 100 (1)

Thus, the potential retention (Vk 5) (%) at 5 seconds after charging was obtained. Next, using a halogen lamp as a light source, the photosensitive member was irradiated with 1.0 kW / cm 2 exposure light spectroscopically at 780 nm for 5 seconds from the time when the surface potential became -600V, and the surface potential was -300V. The exposure amount required to attenuate the light until it was set to E1 / 2 (μJ / cm 2) and the residual potential on the surface of the photoconductor after 5 seconds after exposure were evaluated as Vr 5 (V).

<Practical Characteristics>

The photoconductors produced in Examples 1 to 12 and Comparative Examples 1 to 6 were mounted on an HP printer LJ4050, which was adapted to measure the surface potential of the photoconductor, and 10000 sheets of A4 paper were printed. The film thickness of the photosensitive member before and after printing was measured, and the average wear amount (micrometer) after printing was evaluated. The average amount of abrasion is a value obtained by measuring the film thickness with respect to four points rotated by 90 ° in the circumferential direction at the position of the center (130 mm from the end) in the longitudinal direction of the photoconductor. Moreover, the cloudiness and the density of black paper on the white paper after the initial stage and after 10000 sheets were observed. The case where there was no cloudiness and concentration fall was made favorable.

[0083] [Table 3]

[0084] [Table 4]

From the results in Table 4, in the charge transport layer, in Examples 1 to 12 using a combination of a charge transport material, a resin binder, and a surface-treated inorganic oxide filler satisfying the conditions of the Hansen solubility parameter, wear resistance was good. At the same time, it can be seen that the electrical characteristics as the photoconductor are good, and the image quality is good, either initially or after printing 10,000 sheets. On the other hand, in Comparative Examples 1-6 which did not satisfy the conditions of the said Hansen solubility parameter, the amount of film abrasion after having endured printing was large, or the image had a blur, and the fall of printing density was also confirmed. Moreover, in each Example, it turns out that the wear resistance of a film | membrane improved compared with the comparative example which did not add an inorganic oxide with the improvement of membrane strength.

By the above, by forming a charge transport layer comprising a charge transport material, a resin binder, and an inorganic oxide filler subjected to surface treatment satisfying the conditions of the Hansen solubility parameter according to the present invention, there is no image defect while suppressing abrasion. It was confirmed that the electrophotographic photosensitive member from which a good image can be obtained can be provided.

1; Conductive base
2; Undercoat Layer
3; Charge generating layer
4; Charge transport layer
7; Photosensitive member
21; Charging member
22; High voltage power
23; Image exposure member
24; Developing machine
241; Developing roller
25; Feeding member
251; Paper feed roller
252; Feed guide
26; Warrior charger (direct charge type)
27; Cleaning device
271; Cleaning blade
28; Antistatic member
60; Electronic photo device
300; Photosensitive layer

Claims (6)

Conductive base,
An electrophotographic photosensitive member comprising a charge transport layer provided on the conductive base,
The charge transport layer contains an inorganic oxide filler surface-treated with a charge transport material, a resin binder, and a silane coupling agent,
The said silane coupling agent is either chosen from C1-C5 shown below,

The difference ΔSPa of the force term between the dipoles of the Hansen solubility parameters between the charge transport material and the silane coupling agent satisfies the relationship of ΔSPa <1.0,
The difference (ΔSPb) of the London dispersion force term of the Hansen solubility parameter between the resin binder and the silane coupling agent satisfies the relationship of ΔSPb <2.5.
Electrophotographic photosensitive member. The method of claim 1,
The resin binder is a polycarbonate resin or a polyarylate resin
Electrophotographic photosensitive member. The method of claim 1,
The inorganic oxide filler has a primary particle diameter of 1 ~ 200nm
Electrophotographic photosensitive member. The method of claim 1,
The charge transport material is a hole transport material
Electrophotographic photosensitive member. The method of claim 1,
On the conductive base, at least an undercoat layer, a charge generating layer, and the charge transport layer are provided in this order.
Electrophotographic photosensitive member. The electrophotographic photosensitive member according to claim 1 is mounted.
Electronic photo device.

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